Dental pin for artificial teeth.



H. A. EDWARDS & E, A. SHILLING.

DENTAL PIN FOR ARTIFICIAL TEETH.

APPLICATION FILED DEO.20,1912.

Patented Jan. 6, 1914.

1970 mew UNITED STATES PATENT ()FFIQE.

HERBERT ARTHUR EDWARDS, OF LONDON, AND EDGAR ALFRED SI-IILLING, OF BAB- NET, ENGLAND, ASSIGNORS TO DENTAL MANUFACTURING COMPANY, LIMITED, OF

LONDON, ENGLAND.

DENTAL PIN FOR ARTIFICIAL TEETH.

Specification of Letters Patent.

Application filed December 20, 1912.

Patented Jan. 6,1914.

Serial No. 737,349.

To all whom it may concern.

Be it known that we, HERBERT ARTHUR Enuxlnns, a subject of the King of Great Britain, residing at Alston House, Newman street, London, England, and EDGAR ALFRED SHILLING, a subject of the King of Great Britain, residing at 3 Bedford Mansions, Redford avenue, Barnet, in the county of Hertford, England, have invented new and useful Improvements in Dental Pins for Artificial Teeth. of which the following is a specification.

It has been common practice to provide artificial teeth with openings extending to the rear or labial faces and to embed in the soft porcelain of the teeth platimun tubes adapted to receive and form anchoring pieces for the stems of the silver or base metal pins which are soldered to said anchoring pieces after the process of firing. Such anchoring pieces have been formed of split tubes or wire in order to avoid the stress upon the porcelain surrounding them due to the difference in contraction of such anchoring pieces and the porcelain. This method of securing the dental pin to the tooth has the disadvantage that it is difficult to satisfactorily attach the pin; further the process of soldering the pin to its anchor adds considerably to the cost of production; and for these reasons it is now more usual to first embed the pin head in the soft porcelain and to fire the tooth with the pin in position.

()ur invention has reference more particularly to that class of tooth known as the poured tooth formed in a mold into which the porcelain is poured in asemiliquid state.

Our invention is designed to provide an independent body of platinum or similar metal surrounding the embedded portion of the pin and so constructed, that it engages with the pin only at one end, leaving a space between it and the main portion thereof, thus obtaining a firmer anchorage of the pin in the porcelain of the tooth when a platinum pin is used, and very much increasing strength of the tooth. The independent body of platinum of our invention has the further advantage that it avoids the formation of small cracks and fissures in the porcelain surrounding the pin which usually occur when such a pin is formed partially or wholly of base metal owing to the difference in expansion and contraction of such metal or combination of metals and the porcelain during the process of firing. By means of its outer undulated or corrugated surface, this independent body moreover obtains a very firm hold of the surrounding porcelain.

It is well known that any platinum or other pin tooth is weaker after being backed and soldered for plate cases, probably owing to minute cracks in the porcelain due to the intense heat necessary for soldering. It is found that the introduction of the independent platinum body only and engaging the head of the pin, but for the main part loosely surrounding the pin, obviates such cracks and results in a much stronger tooth after backing and soldering. It is well known that, in all classes of teeth if the pins are carelessly bent, there is a liability for the porcelain to be fractured around the pin. (-ur invention also obviates the possibility of this occurring. as the loose metal body acts as a buffer between the pin and the porcelain.

According to the preferred form of our invention we surround the pin with a coiled wire of platinum or the like metal of suitable length. This coil. is adapted to he slipped freely over the pin to a position just under its head. The headed pin with the wire spiral in position is then embedded in the soft porcelain of the tooth. It is found that with the addition of such a spiral to the pin the anchorage of the pin in the porcelain very much firmer than heretofore and consequently the strength of the tooth is very much increased. \Ve do not limit ourselves to any particular shape or section of the wire from which the coil is made. It must also be understood that we are not limited to the use of a coiled wire but instead of such a wire any equivalent mechanical device can be used. for instance the body or casing can be in the form of a sheath or coller of platinum or other suitable metal adapted to slip loosely over the pin to a position just under its head and such a sheath can be whole or split and its surface plain or corrugated or otherwise roughened.

Our invention is illustrated by way of example in the accompanying drawings on an enlarged scale in which Figure 1 shows an isometric sectional view of a tooth with the pins in position. Fig. 2 shows a back view of the tooth shown in Fig. 1. Fig. 3 shows a detail View of the pin shown in position in Figs. 1 and 2 and Figs. 4 and 5 show an alternative form of our pin.

Refering now to Figs. 1, 2 and 31 indicates the tooth. 2 indicates the pin which may be conveniently as illustrated a base metal headed pin sheathed in platinum. 3 indicates the coiled wire which as illustrated in Fig. 3 is slipped freely over the pin to a position just under its head 9 and is then embedded with said pin head in the soft porcelain of the tooth.

e illustrate by way of example in Figs. l and 5 an equivalent device. In Figs. 4 and 5 we show a headed pin in which the independent body is formed from an angular resilient sheath 8 slipped loosely over the pin to a position just under its head.

Although we have described our invention as more particularly applied to that class of tooth known as the poured tooth formed in a mold into which the porcelain is poured in a semiliquid state, it should be understood that the pins of our invention are equally applicable to that class of mineral tooth which is manufactured largely in the United States and is made on the method known as paste. It is well known that with such teeth where ordinary headed pins are used there is a great probability that during the process of firing or subsequent soldering for plate work that small cracks or fissures will be formed in the porcelain surrounding the pin owing to the difference in the expansion and contraction of the porcelain and platinum or other metal of which the pin may be made. Experiment has shown that in such teeth the use of the loose casing of our invention at the head of the pin is adapted to entirely counteract the difference in the eX- pansion and contraction of the porcelain and the pin during the process of firing.

WVhat we claim is 1. In a dental pin, the combination of a metal pin, a head at the end of said metal pin and an independent casing of metal adapted to loosely surround the shank of said metal pin under said head and to be embedded with said head in the soft porcelain of the tooth before firing.

2. In a dental pin, the combination of a metal pin, a head at the end of said metal pin and a coiled wire adapted to be slipped freely over said metal pin to a position under said head and to be embedded with said head in the soft porcelain of the tooth before firing.

3. A dental pin of the class adapted to be embedded before firing in the soft material of which the tooth is made, comprising a metal pin and a sleeve having an undulating outer surface for the purpose of taking firm hold in the porcelain, said sleeve engaging said pin at one end and a space being formed along its entire length between said sleeve and said metal pin.

In testimony whereof we have signed our names to the specification in the presence of two subscribed witnesses.

HERBERT ARTHUR EDWARDS. EDGAR ALFRED SHILLING.

Vitnesses ARTHUR J. STEPHENS, LEONARD HAYNES.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

